React Interview Questions and Answers by Scholarhat
- 1. React Interview Questions and Answers Prepare for your React interview with our comprehensive collection of commonly asked questions and expert answers. Boost your confidence and knowledge with these essential insights to ace your React interviews. by Scholar Hat
- 2. What is React? React is a JavaScript library for building user interfaces. It allows developers to create reusable UI components and efficiently manage the state of these components. React uses a virtual DOM, which improves performance by minimizing actual DOM manipulations, making it a popular choice for building interactive and dynamic web applications.
- 3. What are Components in React? Reusability: Components enable reusing the code, making it easier to maintain and update. Separation of Concerns: Each component represents a specific piece of the user interface, allowing for better organization and readability. Encapsulation: Components encapsulate their own functionality and styling, reducing interference with other parts of the app.
- 4. What is JSX? JSX Syntax JSX is a syntax extension for JavaScript, often used with React, that allows for writing HTML elements and components in a JavaScript file. Embedding Expressions JSX allows embedding expressions inside curly braces, making it easier to work with dynamic content and data. Compile to JavaScript JSX code is transpiled into regular JavaScript code using tools like Babel, enabling developers to write familiar HTML-like code.
- 5. What are Props in React? 1 Data Flow Props allow the flow of data between components in React. 2 ReadOnly Props are read-only, meaning that the data coming from the parent should not be changed by the child component. 3 Customization Props enable the customization of components based on the data passed to them. 4 Reusability Props promote component reusability by allowing different data to be passed to the same component.
- 6. What is State in React? Local Data State allows React components to hold and manage local data. Dynamic UI It enables dynamic and interactive user interfaces in React applications. Component Control State helps in controlling the behavior and appearance of a component.
- 7. Explain the lifecycle methods of a React component. 1 Mounting Occurs when an instance of a component is being created and inserted into the DOM. 2 Updating Occurs when a component is being re-rendered as a result of changes to its props or state. 3 Unmounting Occurs when a component is being removed from the DOM.
- 8. What are Hooks in React? Stateful Logic Allow functional components to manage state and lifecycle features. Improved Code Reusability Enables the reuse of stateful logic without changing component hierarchy. Enhanced Readability Helps in organizing and isolating stateful logic for better code readability.
- 9. How do you handle events in React? 1 Event Handling Bind event handlers to components 2 Event Types Understand different event types in React 3 State Updates Update the state based on events Handling events in React involves binding event handlers to components, understanding different event types, and updating the state based on events. It's essential to ensure smooth user interactions and dynamic component behavior.
- 10. What is a Higher-Order Component (HOC)? 1 Reusable Logic Encapsulates common behavior for reuse 2 Enhanced Components Wrap other components to provide additional functionality 3 Flexible Composition Composes components in a flexible and scalable manner